brookter wrote:In Lingua Latina Cap XII there is the following sentence:

Circum castra fossa et vâllum longum et altum est.

Why isn't 'sunt' used here? Would it be incorrect (and if so, why?) or is it a matter of style?

A singular verb can serve as predicate of multiple subjects, as in English.cf. Livy, XXXI, 18, 3: 'aetas' inquit 'et forma et super omnia Romanum nomen te ferociorem facit'.The Lingua Latina example might have been more natural if est had come after fossa rather than at the end of the sentence.

hi, i think it would be strange to have sunt here, not est, in golden age latin at least, because the subjects are things and not persons, and none of the rules about when 2 subjects which are things take a plural predicate seem to apply here - in your case the predicate agrees with the closer subject, vallum.

here is a copy-paste of my summary of what lebreton (in a book about cicero's grammar and syntax) says about when a predicate with multiple subjects (as in your case) takes the singular and when it takes the plural.

there are of course some exceptions to these rules as lebreton notes, but they are nonetheless pretty solid rules or definite patterns - see lebreton's book for the statistics of each rule:

The rule is that the predicate agrees with the subject closer to it, except as set out below:

It agrees with the further subject, not the closer, where further is abstract plural, closer is abstract singular: Sin quaestiones habitae aut postulatio, ut habeantur, causam adiuvabunt, Part.Or.34.117 (p.5)

It is plural where:- The attribute is "genera sunt". Si deliberatio et demonstratio genera sunt causarum, Inv.1.9.12 (p.5)- The attribute is "corpora sunt". Ignis, anima, aqua, terra corpora sunt, Ti.14.50 (p.8 )- (if the closer and further are persons, see specific rules in the next para.)- The further is a person and the closer is something personified: principes sint patria et parentes, Off.1.17.58 (p.10)- The closer is an abstract name of a population, equivalent to "gens" + the gen pl name of the people, and the attribute agrees with this implicit gen pl name of the people. Cilicum autem et Pisidarum gens, et his finituma Pamphylia, quibus nationibus praefuimus ipse Div.1.1.2 (p.10)

Where X and Y are persons, the following rules apply:- If it falls between them, it agrees with the first: Catulo audiente et Caesare, De Or.2.10.40 (p.17)- If it comes before both, it agrees with the first: Quod ait Aristoteles et Theophrastus, Or.68.228 (p.17)- If it falls after both, there are 4 rules: 1. it agrees with the closer if each person has a different adjective: Suavitatem Socrates, subtilitatem Lysias, acumen Hyperides ... habuit, De Or.3.7.28 (p.19)2. it agrees with the closer if each person has before it the same word repeated, whether conjunction, adjective etc: et Cotta et Sulpicius expectat, De Or.2.7.26 (p.21)3. it agrees with the closer if aut, vel, ve or sive connects them: Aristophane aut Callimacho tractante, De Or.3.33.132 (p.22)4. otherwise it is plural: Philodamum et filium esse damnatos, Ver.1.28.71 (p.14)